s14 into e21 swap guide.

[nikch86]

Hello everybody.
Let me write an organized swap guide so it can be added to

http://forums.bimmerforums.com/forum....php?t=1146050


Lets start.


Things that you will need for the swap:

Complete S14 engine with all the sensors. It you do not get the tranny, make sure to get two sensors that are on the bell housing of M3 tranny near slave cylinder. You do not need the third one that is alone on the top of the bell housing.

S14 engine wiring harness and ECU. It splits in two and one side goes into the glove box where it connects to the ECU. The other side goes to the other side and right above brake booster it connects to the chassis harness via C101 connector. It's a big rounded connector. It is better to get both sides of C101 connector because it will make wiring a lot easier and cleaner.

Transmission. Since S14 has the same block as the M10, your tranny will bolt right up. The only problem are those two sensors that are mounted on the M3 bell housing. Without these sensors, engine will not run! One is for TDC and the other for RPM. The solution is to weld two aluminum bosses to the tranny from M10. I used the service of this place:

http://www.2002parts.com/html/m2_kit.html

They charge $475 for this + shipping but they do it well. You will have to send them your bell housing or par a $100 core charge. Final result looks like this.


The other option is to use E30 M3 Tranny. That way, you will avoid these modifications. But, m3 tranny has a different output shaft, so it will not bolt to your drive shaft. You will have to get a flange that will match M3's flange and weld it to your drive shaft. Also, M3 has a different shifter assembly. I do not know what will be needed to make it work. There is also a possibility that M3 tranny will not fit in your tunnel. I did not use one, so cannot confirm.

Exhaust. You will need a custom exhaust because no one makes one for this application.
I solved it by buying an aftermarket 2.5" stainless steel exhaust from 1988-91 Honda CRX for $160 with shipping from eBay and cutting it in a few places to match stock bends. This is how it looks.

And now cut.





Also, you will need a Y-pipe to connect to s14 header. You can get the cutout of E30 M3's x-pipe or make a custom y-pipe. I got mine from the same place where they modified my bell housing.

You will also need a M3 overflow tank that is located near firewall on the passenger side of E30 M3 or something else that would work in it's place.

Make sure to get a thermostat and all the hoses that go with it from M3 because the M10's thermostat is different. It may work with some mods.


This is about all you will need for the swap.

Ok. Here is how the swap goes.

First take your engine and tranny out.
While the engine is out, do some preps. Cut out battery tray, stock airbox support, remove radiator. Remove the braided lines on the fuel line. Return line will have a clamp, so it's easy. You will need cut a nut off the other fuel line but only a nut! I used a grinder just make sure you do not blow yourself and your car! After that, you will have a nice metal line just like a return line. You will do that because S14 uses rubber hoses for both.

After that remove the engine mounts from your M10 and bolt them to S14. They will you different holes than e30 M3 mounts and will be further forward.
Then, you have an option. You can ether use S14 oil pan which will require some trimming or M10 oil pan. If you use M10 oil pan, you won't have any clearance problems but you may need to swap oil pickup as well. I'm not sure.

If you use S14 oil pan with M10 tranny, the hols for the bolts in the bottom of the tranny will not match up with the hols on S14 oil pan but do not worry. Now it's time to take a grinder and shave off those bumps in the bottom of the S14 oil pan that did not match with your tranny as they will hit the steering rack and cause vibration. Do it while the engine is out. It is a lot easier. I found it the hard way... Even then, the clearance between the oil pan and the steering rack will be about 1.4". See picture.


You will need to trim a little piece off the subframe to accommodate huge S14 oil pan.


Now, put the engine in. It should fit like it was made for E21.

Then come all the little things.

These are the things that will need some fabrication.

Throttle cable from from M10 is too short. Here is what I did. All these things a found in a hardware store and cost a few $.


Then you will need to mount the ECU. I mounted it right above the glove box and you can use the holes from the AC lines for the wires to the ECU.
It will take a while to get one of the holes big enough to get the rubber grommet in. Just try to get it as high as possible so it will not eat ut the space in the glove box. Do not forget to ground two bundles of wires near the ECU. Here are the pictures of my installation.




There will be a little black wire near the main and fuel pump relay peal the black and you will see that it is red. It's +. So you will need to connect this little red wire with the big red that used to go to the + terminal on M3. Then connect them to a good thick wire and run them to the trunk where you will have the battery now. You can you the second hole from the AC piping next to the wires that go to ECU. It's just easy that way.

Here is how you wire engine harness to your car. E21 has a rectangular connector on the side of the fuse box. Leave about 2 fete of wires on that connector and cut the rest off. This is when you will need the other side of C101 connector from M3. There will be a lot of unused wires such as: SRS light, engine check light, oil static... Here is the diagram of C101 connector from M3.

Here is a scan of the page of M2 swap. It's for BMW 2002 so the colors are different but you will have idea what wires to use on C101 connector.


I had some problems finding out what wire on E21 chassis is for position ON and what for position START. Even the wiring diagrams were not real help. The best way is to take a test light and check each wire. For some strange reason, when we connected pins 15 and 18 from C101 to a wire that was hot on position Start, the starter would spin but the solenoid would not engage. So we disconnected the THIN wire ether pin 15 or 18? and left the thick connected. Then, engine fired right up.

The clutch fan from s14 will not clear the radiator, it you have a 80+ e21 you can move it forward a bit. Otherwise, you need to remove it and install an electric fan but even then, the distance between the radiator the the water pump pulley is only 2 1/4" so even the thinnest fan I found was 2.5" thick.
My solution was not to put fan in the center of the radiator but to move it to the right side. Look at the picture.


The radiator hose is pretty easy. S14 lower hose will fit on E21 radiator no problem. The top needs a little improvisation. I used lower radiator hose from M10 to go around distributor, then I went to a hardware store a got I think 2" chrome drain extension pipe for $10. After, I used the upper hose from M10 and cut a 90degree elbow from it.

Then, you have to find a place for the overflow tank. I used M3 tank and mounted it may be in not the best place, but at least it was easy. You may try to use another overflow tank and mounted it some place else, but make sure, it is just a little above radiator.


The air box from M3 fits but the lower air inlet hits a metal wall so unless you want to start cutting it, just use a short K&N filter. You will need to mount the MAF somehow. The guy I got the engine from had a cold air intake that had a special bracket to hold MAF. With some modifications it fitted right. And one more thing, some people were saying that if you have 77-79 e21 you will have master cylinder hitting the intake pipe. Mine is 1977 and is ok. May be it has a 80+ master cylinder. I do not know.


Finally the exhaust. Here are the pictures of how it finally came out.








This is pretty much it as far as I remember. If you have any questions feel free to ask. I hope it will be a good swap guide.

Thanks everybody.

[switlikbob]

Thanks for this great write up! How did you get the e21 coolant temp sensor (the one that shows water temp on the gauge cluster) hooked up? Also, why did you use the s14 oil pan and not the e21 oil pan?

[Tom D]

bob, he hasn't posted here in a long time, in fact it appears that he is now camped out on the E39 forum.

while i admire his attempt, that has to be one of the sloppiest engine bays i ever saw. oh, and to answer your question, it was far easier for him to cut away the structure of the subframe then to weld a return pipe to the M10 oilpan for the oil separator.

[switlikbob]

Thanks Tom. It is a ragged bay, no doubt, but it has an S14 in it! Cutting the subframe in the e21 is just scary IMHO. Are you talking about welding the m10 oil pickup to the s14 pump? I am not familiar with the oil separator.

I really, really, think that I am going to swap an s14 into my car. Any help from you, or anyone else (especially someone who has done it) would be fantastic

I do plan on paying Dave at Aardvark for his M2 instructions, Y pipe and bell housing bung welds. I love Dave!

[Tom D]

this is how you do a S14 proper. http://www.m2bmw.com/roy-wicklund.htm

[1981320i]

this swap looks pretty hack, cutting a subframe is very cheap and not a proper solution. i dont even want to get into that exhaust looks like it was welded by a virgin welder. s14 should have gone to someone that would have shown it proper love not slapped it in something

[jrcook320]

This sort of swap short circuits my wiring. I pretty much have no interest in the build. I can't fathom spending the money on an S14 only to spend zero time on a) doing it right and b) a little presentation.

Cleaning the hacked edges of the "clearanced" areas, degreasing the engine, painting the engine bay, and locating things in places so they don't need cut takes a little time and effort but goes a long way. It doesn't have to be show quality (like that orange m2), but there is no reason a swap like this can't at a minimum appear to be a factory installation.

Cutting the subframe at that gusset without boxing it back in somehow is completely unacceptable, that is a structural area.

[DEZIAC]

I have a local friend that has an S14 in his e21. Here's some pics of the donor e21, which has some interesting bits on it. At my parents right now, when I get home I'll try and see if I have some pics of the cleaned up S14 in the new body. Oh and I'll ask him if its okay to give out his email address for any questions.






zender side skirts and tsw hockenheims, which I owned for about 2weeks...lol


ASS seats..or Auto Sport Spezialsitze...damn I snoozed on those joints


Big/Small hella grill (which I now own, along w/ the suspension) and this rare Osella front bumper, never seen anywhere else before.

[Tom D]

if i remember right, OP's car was stripped right after it's build and sold off. i believe conkitchen bought the shell for the motorsport front bumper. i don't know what happen to the engine.

[switlikbob]

I'll ask him if its okay to give out his email address for any questions.

That would be great! I certainly have some questions to ask him. If you wouldn't mind giving him my email address: switlikbob at hotmail_dot_com

[Jazziat]

OMG ..... as if i found the typical subject that i wanted to watch .... I am doing the same within 2 weeks into my E-21

S14B20 swap ... and i just noticed the issue of the oil pan ... and cutting the sub-frame ... is totally unacceptable for me.

Would someone please explain using the original M10 oil pan ... and what is the oil pack and to where is goes ....

Also i heard that the airbox hits the oil brake bottle (sorry for the naming).

Thanks
Jazziat

[Tom D]

in his picture below there is a rubber hose going to the top of the pan. this is a oil return line that comes from the oil separator. the oil separator is part of the positive crankcase valve. it's job is to separate the air/oil coming out of the vent on the valve cover, sending the air to the intake and the oil to the crank.

all you need to do is weld a pipe onto the side of the M10's oilpan. that's it.

Also i heard that the airbox hits the oil brake bottle (sorry for the naming).

i cannot tell you if it would hit or not , but if it does then the 2002 had a remote brake reservoir. use it instead. in his photos above it looks like he clears without problem.

[switlikbob]

So Tom D, being that my oil pan is already tapped for the turbo oil return line, can't I just use that? I know it's on the other side of the pan, but hose is cheap and I am sure I can get it pitched properly...right?

[Tom D]

i see no reason for it not to work.

[switlikbob]

Can anyone answer my question concerning the oil pan? Is the oil pump pickup in the same location on the M10 as the s14? Is the m10 oil pan a straight swap onto the s14?

[Layne]

Can anyone answer my question concerning the oil pan? Is the oil pump pickup in the same location on the M10 as the s14? Is the m10 oil pan a straight swap onto the s14?

The pickups are not the same, but are interchangeable. The oil pan will bolt on easily, all bolt holes in the block are the same.

[archangeljx]

I seriously started reading this thread thinking we were talking about puting a Nissan S14 engine into an E21...

[switlikbob]

The nissan s14 motors are nice too! But there's nothing like an ///M engine

[Layne]

The complete lack of replies to the original post pretty much says it all. Total hack job. I checked through his old threads. Car was bought in 8/09, engine was in by 11/09, car was immediately for sale, and being parted out by 1/10. I hope the chick with the S62 plans is reading this.

[Tom D]

what chick is that?

edit; i remember. ninjabunny, the girl who's boyfriend was going to make her work an extra job so she could finance him to build himself an e21 drag car and then take it auto-xing. nice guy!

[m20powered]

while i admire his attempt, that has to be one of the sloppiest engine bays i ever saw.

To be fair, that`s only because you must not have seen my engine bay (and mine has an M10 in it!)

[jjgbmw323]

This sort of swap short circuits my wiring. I pretty much have no interest in the build. I can't fathom spending the money on an S14 only to spend zero time on a) doing it right and b) a little presentation.

Cleaning the hacked edges of the "clearanced" areas, degreasing the engine, painting the engine bay, and locating things in places so they don't need cut takes a little time and effort but goes a long way. It doesn't have to be show quality (like that orange m2), but there is no reason a swap like this can't at a minimum appear to be a factory installation.

Cutting the subframe at that gusset without boxing it back in somehow is completely unacceptable, that is a structural area.

Yeah its hacked, and I am taking the time to make mine engine swap correct, which is resulting in a shaved and repainted engine bay with the fuse box relocated out of site, and powdercoated parts, as well as a fresh cermaic coating of the headers. There is no way I would ever hack a subframe like that guy did. I am going for a clean Show quality install.

Josh I admire your car and your work...

[switlikbob]

While my swap won't be show quality, it will be done right.

[Tom D]

my m42 certainly is not show quality, it's not my thing, but at least have pride in workmanship.

[Jeff M3]

my m42 certainly is not show quality, it's not my thing, but at least have pride in workmanship.

Looks great. There's like 11 feet in front of that engine. How long did the swap take (in terms of working hours... Not overall time elapsed)?